Wobbler actuating piston for barrel engines



sept. 7, 1937. H, ALFARO 2,091,949

WOBBLER AGTUATING PISTON FOR BARREL ENGINES Filed ont.4 1e, 1955 2 sheets-s119911 57 l I 6 4 /8 Z5 58 j /0 3 g (1275/ 2 22 1.3 1 l/ INVENTOR F1' 7. 4- Henaczio azfara V BY VW T )46c/C7 ATTORNEY Sept. 7, 1937.

H. ALFARO WOBBLER ACTUATING PISTON FOR BARREL ENGINES Filed Oct. 16, 1955 2 Sheets-Sheet 2 INVENTOR Heraclo Alfaro vzaMA b- 144,06

ATTORNEY Patented Sept. l7, 1937' UNITED STATES PATENT -oFElcE WOBBLER ACTUATING 'PISTON FO BARREL ENGINES The present invention relates'to engines of the wobbler cam or barrel type, particularly engines of the two-stroke cycle type having two pistons per cylinder. the improvements being in the cam actuating Apistons of such engines andparts associated with the pistons. lAn engine .of the type referred to is disclosed in niy'co-pending application Serial No. 710,428, ledFebruary 9, 1934. -The present application is in parta con'- tinuation of the aforesaid application.

The present invention has for an object to provide a piston which has eiective means for applying thrust to the wobbler cam and for receiving the thrust of the cam.

A further object is to provide a piston provided with means for rigidly supporting cam engaging thrust rollers and so constructed as to readily permit mounting or removal of the rollers.

A further object is to provide automatically operating means for lubricating'the bearings of the thrust rollers during operation of the engine.

With the above and other objects .in view the invention may be said to comprise the piston as illustrated in the accompanying drawings hereinafter described and particularly setv forth in the appended claims together with such variations and modifications thereof as will be apparent to one skilled in the art toy which the invention appertains.

Reference should be had to the accompanying drawings forming a part of this specicatiom i which:

Figure 1 is a longitudinal section through one of the pistons showing portions of the associated cylinder, wobbler cam and engine shaft;

F.g. 2 is a top p.an View othe outer end of the piston shown in- Fig. 1;

Fig. 3 is an end elevation looking at the outer end of the piston;

Fig. 4 is a sectional view showing apiston ef slightly modied -construction;

. Fig. 5 is 'an end elevation of the piston shown in Fig. 4; v

Fig. r6 is a sectional view showing a piston embodying the invention in which the skirt is of f composite sheet metal construction;

Fig. 'I is a section taken on the line indicatedi at 1-1 in Fig. 6;

Fig. 8'is a section taken on the line indicated at8- 8inFlg.6;

. Fig.. 9 shows the oil scraping ring in elevation;

Fig. 10 is a plan view of the oil scoop bracket viewed as indicated at IO-,III in 3.

In the accompanying drawings there is shown one of the cylinders I of abarrel engine which is disposed parallel to the central engine shaft 2 to which is attached a wobbler cam 3 through which the lineary movements of the pistons im.

part rotary motion to the shaft. One of the pistons 4 is shown, it being understood that all of the pistons of the engine are alike.

The piston 4 has a tubular skirt 5 which may be formed integrally with the head of the piston. The skirt 5 is preferably stiffened by regularly spaced longitudinally extending .internal ribs 6. Two diametrically-opposite ribs 6 terminate at their outer ends in bearing'bosses 'I and 8, one on the side of the skirt adjacent the shaft 2 and the other in the outer side of the skirt. A bore isc'ut through the skirt 5 and boss 'I at an oblique angle to the piston axis and an alined bore is cut into the innerboss 8 to a depth suiiicient to form a socket fora tubular shaft 9 which seats at its opposite ends in the bosses I and 8. The shaft 9 provides a bearing for a beveled thrust roller I0 which rolls upon the inner face of the cam 3.

The `outer portion of the skirt 5 has an integral extension II which at its outer end has integral theinner ends of the arms I2, the extension II' has a thickened central portion I5 provided with an oblique opening to rec'eive a bolt I6 which secures in place a short shaft I'I which provides a supporting'bearing for a beveled follower roller I8 which rolls upon the rear face of the wobbler cam 3 and serves to prevent excessive axial play` between the piston and cam.

The outer'end of the inner side of the skirt 5 is separated from the body of the skirt in a plane across the center of the boss 1 as indicated at I9 in Fig. 1 to form a detachable member 20 which is secured to the body of the skirt by bolts ZI screwed into apertures in the halves of the boss 1.

To msunt the bevel roller IU within the skirt 5 the detachable member 2U is removed, the roller I 0 is slipped into place between the bosses I and 8 and the shaft 9 is inserted through the roller into the socket inthe boss 8 after lwhich the p0rtion'2 is bolted inplace. The shaft 9 4is held againstturning 4movements by a dowel 22. Av thrust washer 23 is interposed between the roller I0 and the boss 8 and a dowel 24 holds the thrust washer against turning movements.

The cam 3 has the peripheral roller engaging .portion 25--thereof offset inwardly with respect may be attached to the cam to prevent any oil beingthrownawayfromthefaceofthecam. The baille plate 2l flares inwardly from the face of the cam and has an outer marginal portion which is positioned close to the face of the cam so that any oil moving outwardly either on the. surface of the cam or the inner face of the baille plate is directed in a thin iilm outwardly to the internal shoulder 23.

A passage 3i is formed in the detachable member 2l of the skirt and extends from the oil collecting scoop to the opening in the boss I registering with an aperture 32 in the shaft 0 to deliver oil to the interior of the shaft. The opening through the boss 1 is closed by the inner end portion 33 of the detachable member 2li to prevent leakage of oil `and the hollow shaft l has an opening 34 midway between its ends on the side opposite that against which the thrust of the roller is exerted. I'he opening 34 delivers oil to the bearing of the roller I0 on the side where there is the least pressure so that there is an ample supply of `oil to the roller bearing. Near its outer end the shaft 0 has an opening 35 which permits iiow of oil from the interior of the shaft 9 to a passage 38 extending through the extension Ii to the roller supporting portion I5. The bolt I6 is provided with an axial passage 31 which delivers oil from the passage 3l into the interior of the shaft llwhich has a lateral opening 33 to the roller bearing. Lateral passages 30 in the arms I2 deliver oil from the passage 36 to the cross head bearings I3.

During operation of the engine, oil is automatically delivered from the cam face to the bearings of the thrust and follower rollers and to the crosshead bearings.

In engines of the two-stroke cycle type having opposed pistons in each cylinder and ports open-l ing through the cylinder wall. it is diiiicult to avoid leakage of oil into the ports and to the combustion chamber due to the scraping of oil oil.' the piston skirt into the ments of the piston past the ports.

At the open end of the cylinder I there is mounted an oil scraping ring 4l which engages the piston skirt 5 which sweeps the oil from the exterior surface of the skirt during the inward stroke of the piston, thereby saving oil which wou1d otherwise be scraped os into ports in the cylinder wall and leak into the space ahead of the piston and be consumed with the fuel.

Ihe oil scraping ring 43 is a resilient split ring which may be constructed like an ordinary piston ring mounted in a retaining ring 43a detachably secured to the end` of the cylinder and is backed by a spring 40h interposed between the exterior periphery of the ring 4l and the bottom of the channel formed between the ring 43a and the edge of the cylinder, the spring 43h serving to maintain a suitable pressure between the interior of the ring 4I and the surface of the piston skirt. The portion of the skirt i with which the scraper ring 4l engages preferably has a continuous smooth cylindrical surface without recesses in which oil can accumulate so that the skirt can be swept clean by the scraper ring. The exterior lirface of the closure forming portion 33 ofthemcmber Zlismachinedtoconformtothe exterior surface of the skirt so that there is no recess for accumulation of oil at the opening through which the roller shaft 3 is inserted.

In Figs. 4 and 5 of the drawings there is shown a slightly modified construction in which the piston skirt 3a is provided with internal bosses to the roller bearing.

Ports during move- 4| man annemriersndouradesmereofm "support a tubular obliquely disposed' shaft 43 vskirt wall at the inner end of the shaft and through the head 43. A dowel 43 is provided to hold the shaft 43 against rotation. A crosshead extension 4l is detachably secured to the body of the skirt outwardly of the boss 42 by means of bolts 53. 'I'he thrust roller 44 is inserted into the outer end of the skirt 5a before the extension 49 is attached and after the roller 44 is positioned between the bosses 4I and 42 the shaft 43 is 'inserted and secured in place.

The wobbler cam 3a has its marginal thrust roller engaging portion inwardly voffset and within the shoulder o'f the cam there is provided an 'oil groove 5l into which oil is directed by the inner face of the cam and the baille 29a.

An oil'scoop in the form of a tubular member 52 is secured to the end of the skirt body outwardly of the boss 4I by bolts which are screwed in the apertures llshown in Fig. 5. The scoop has a. laterally bent outer end portion- 54 positioned in the oil groove 5I of the cam. A passage Si in the skirt leads from the oil scoop to the socket in boss 4| and the shaft 43 has an aperture 58 registering with the passage 55. Midway between its ends the tubular shaft 43 has an opening 51 through which lubricant is supplied At its outer end the shaft 43 has an aperture 53 opening to a passage 5! in the skirt 5a which leads to a passage Bil in the cross head extension 49 from which oil is supplied to the bearing of the follower roller and to the cross head bearings.

In Fig. 6 of the drawings there is shown a plston having a head Il which may be formed of an aluminum alloy or other suitable metal having high heat conductivity and a thin'metal skirt 32 formed of sheetsteel or steel tubing and secured to the head Si by suitable means'such as bolts I3. Supporting bosses 65 and 64 for opposite ends of a thrust roller supporting shaft may be secured by welding or brazing to the interior ofthe skirt 32, the skirt 82 being provided with an Yopening registering with the inner socket I4 to permit the roller supporting shaft to be inserted. In order to permit the thrust roller to be inserted into the skirt ascoop extension 6l is provided which is detachable, the inner end of the extension closing the open end' of Vthe socket 34 and being detachably secured to the socket by bolts as in the modification shown in Fig. 1- The skirt 62 is reenforced interiorly by longitudinal bracing elements 03 which are formed of sheet m'etal and V-shaped to form internal ribs when secured to the interior of 'the skirt 32 by welding or brazing. Two of the bracing' elements vIl are in alinement with the bosses I4 and and are welded or brazed to the bosses.

The bracing members are preferably an integral part of a sleeve 39 which fits within the piston skirt. 'Ihe skirt 62 and sleeve 63 are provided with integral portions extending outwardly of the boss il which are welded orbrazed together to form a hollow extension 'Il and hollow arms 1I extending laterally from the extension 1I. A sleeve 'I2 for supporting the follower roller is welded or brazed to the outer end of the hollow extension 10 and bearing sleeves 13 are welded or brazed to the outer ends of the arms 1I.

Lubrication of the roller and cross head bearings is substantially the same as describedin detail in connection withFig. 1.

` An aperture 14 is provided in the boss 65 through which oil may flow from the interior of. the roller supporting shaft into the hollow extension 10. AnA aperture I5 in the sleeve 12 permits fiow of oil to the bearing of the follower roller. The hollow arms 1I communicate with the hollow extension and apertures 16 'are' provided in the crosshead bearingsleeves I3 to lubricate the same.

It will be apparent that the present invention provides a piston having a rigidly attached crosshead and interiorlymounted cam engaging rollersv which 1possesses, the necessary rigidity and which can readily be assembled in operative relation to the cam and which can be readily disassembled to lpermit repair or replacement of parts.

It will further be apparent that simple and effective means are provided for automatically lubricating roller and crosshead vbearings during operation of the engine, and for preventing `excessive loss of oil through the cylinder ports or by leakage into the combustion chamber.

Furthermore,' it is to be understood that the particular-form of apparatus shown and described, and the particular procedure se`t forth, are presented for purposes of explanation and illustration and `that ,various modifications of said apparatus and procedure can be made without departing from my invention as described in the appended claims.

What I claim is:

1. In an engine having a vshaft with a wobbler cam thereon, a. piston having a roller engaging the cam, means for supplying-oil to a surface of the cam, and means carried by the piston for collecting oil from the surface of the cam. and for delivering oil so collected to the bearing of said roller. .v

2. In an engine having a shaft with a wobbler cam thereon, a piston having a thrust roller and a follower roller engaging opposite faces -of the cam,'means for supplying oil to a surface of the cam, and means carried by the pistonfor collecting oil from the surface of the cam and for delivering oil so collectedto the bearings of the rollers.

3. In an engine having a shaft with a wobbler camsthereon, a piston having a crosshead provided with bearings, means for supplying oil to a surface of the cam, and means carried by the piston for collecting oil from the surface of the cam and delivering oil so collected to the crosshead bearings.

'4. In an engine `having a shaft with a wobbler cam thereon, and a cylinder substantiallyparallel to said shaft, a piston' in said cylinder hav-f ingv a skirt portion, a cam vengaging roller ,hav-

inga bearing within the piston skirt, an oil passage in said skirt for supplylngoil to the roller l' bearing, and means operable during-rotation of the shaft for delivering oil to said passage. A 5. In an engine having a shaft, a cylinder-substantially parallel to the shaft, a wobbler cam on thshaft, a. cam engaging piston in the cylinder having lubricant passages therein, means for maintaining a layer of oil on a face of said cam, means carried byv said piston for collecting oil from said cam surface and delivering the same to said lubricant passages.

. 6'. In a barrel engine having a shaft, a cylinder substantially parallel to the shaft, a wobbler cam on the shaft, a piston in the cylinder having a skirt, an oblique shaft extending across the skirt, a cam engaging roller rotatablymounted on said shaft, means for supplying oil to the side of the cam engaged by said roller inwardly of the p0rtion of the cam engaged by the roller, and means carried by the piston for collecting oil from the face of the cam and delivering the oil so collected through the interior of said roller shaft to the bearing of theroller. v

'1. In a barrel engine having a shaft, a cylinder substantially parallel to the shaft, a piston having lubricant passages, a member extending around the shaft and rotatable with the shaft, means for maintaining a layer of oil on a surface of said member during rotation of the shaft, and means carried by the piston for collecting oil from said surface and delivering oil so collected to said lubricant passages.

8. Ina barrel engine having a shaft, a cylinder substantially parallel to the shaft, a wobbler cam on said shaft, a piston in said cylinder having a skirt, the open end of which is toward said cam, said skirt having an extension on the side thereof away from said shaft, a shaft extending -across the interior of said skirt, a cam engaging roller rotatably mounted on said shaft, a second cam engaging roller carried byy said extension, means for supplying lubricant to a 'face of said cam, and means carried by the piston for collecting oil from the face of the cam and delivering oil to the bearings of said rollers.

9. In a barrel engine having a shaft, a wobbler cam carried by said shaft, said cam having a laterally offset marginal portion `forming an internal shoulder, a cylinder substantially parallel to the shaft, a piston in said cylinder hay-ing va roller engaging the offset marginal portion of -the cam, means for supplying oil to the face of the cam inwardly of said internal shoulder, an oil collecting scoop carried by the piston and positioned closely adjacent said internal shoulder, and means for conducting oil from said scoop to the bearing of said roller.

v10.` In a barrel engine having a shaft, a wob bler cam carried by said shaft, said cam having a laterally offset marginal portion forming an internal shoulder, a cylinder substantially parailel to the shaft, a piston in said cylinderhaving rollers engaging'opposite sides of the offset marginal portion of the cam, means for-supplying oil to the face of the cam inwardly of said internal shoulder, an oil collecting scoop carried by the piston and positioned closely adjacent said internal shoulder, and means for conducting oil from said scoop to the bearings of said rollers.

11. Inv a barrel engine having a shaft, a wobbler cam carried by said shaft, said cam having alaterally offset marginal portion forming an internal shoulder, a cylinder substantially parallel to the shaft, -a piston in said cylinder having rollers engaging opposite sides ofthe offset margina] portion of the cam, and a crosshead having guide engaging bearings, means for supplying oil to the face of the cam inwardly of said internal shoulder, an oil collectingscoop carried'by the piston and positioned closely adjacent said inter-A nal shoulder, and means for conducting oil from said scoop to the bearings of said rollers and 

